How soil granulometry,temperature, and water predict genetic differentiation in Namibian spiders (Ariadna: Segestriidae) and explain their behavior

The Namib Desert is a biodiversity hotspot for many invertebrates, including spiders. Tube‐dwelling spiders belonging to the Ariadna genus are widespread in gravel plains. These sit‐and‐wait predators share a particular behavior, as they spend their life in tunnels in the soil, surrounding the entrance of their burrow with stone rings. We investigated five spider populations taking into account environmental parameters, functional traits, and molecular data. We have chosen the temperature at the soil surface and at the bottom of the burrow, the air humidity, and the soil granulometry to define the environment. The chosen functional traits were the diameter and depth of the burrows, the ratio between weight and length, the thermal properties of their silks, and the number of ring elements. The molecular branch lengths and the evolutionary distance emerging from cytochrome oxidase I gene sequences summarized the molecular analysis. Our study highlights a strong coherence between the resulting evolutionary lineages and the respective geographical distribution. Multivariate analyses of both environmental and molecular data provide the same phylogenetic interpretation. Low intrapopulation sequence divergence and the high values between population sequence divergence (between 4.9% and 26.1%) might even suggest novel taxa which deserve further investigation. We conclude that both the Kimura distance and the branch lengths are strengthening the environmental clustering of these peculiar sites in Namibia.     

Histidine 186 of the nicotinic acetylcholine receptor alpha subunit requires the presence of the 192-193 disulfide bridge to interact with alpha-bungarotoxin

We have previously shown that two histidine residues of the nicotinic acetylcholine receptor are relevant for alpha-bungarotoxin binding. This paper studies: (1) the interaction between alpha-bungarotoxin and the peptide alpha173-202--synthesized according to the sequence of the Torpedo californica receptor alpha subunit--and between the toxin and the same peptide containing His186 modified with ethoxyformic anhydride or substituted by Ala; (2) the influence of the presence of Cys192-Cys193 disulfide bridge on such interactions. Solid-phase and in-solution competition assays were performed: ethoxyformylation of His186 or its substitution by Ala led to a significant drop in the toxin binding capacity only for peptides containing the bridge. Circular dichroism and fourth derivate spectra of all peptides were also analyzed. Results strongly indicate the involvement of His186 in the toxin binding to those peptides with the bridge--also present in the native receptor molecules--but not to their reduced forms; on the other hand, they give further support to the already established premise that, though the bridge does not participate directly in receptor-toxin binding, its presence is relevant to define the appropriate conformation of the interaction area.     

Branched-chain amino acid supplementation promotes survival and supports cardiac and skeletal muscle mitochondrial biogenesis in middle-aged mice

Recent evidence points to a strong relationship between increased mitochondrial biogenesis and increased survival in eukaryotes. Branched-chain amino acids (BCAAs) have been shown to extend chronological life span in yeast. However, the role of these amino acids in mitochondrial biogenesis and longevity in mammals is unknown. Here, we show that a BCAA-enriched mixture (BCAAem) increased the average life span of mice. BCAAem supplementation increased mitochondrial biogenesis and sirtuin 1 expression in primary cardiac and skeletal myocytes and in cardiac and skeletal muscle, but not in adipose tissue and liver of middle-aged mice, and this was accompanied by enhanced physical endurance. Moreover, the reactive oxygen species (ROS) defense system genes were upregulated, and ROS production was reduced by BCAAem supplementation. All of the BCAAem-mediated effects were strongly attenuated in endothelial nitric oxide synthase null mutant mice. These data reveal an important antiaging role of BCAAs mediated by mitochondrial biogenesis in mammals.     

Lubricin is expressed in chondrocytes derived from osteoarthritic cartilage encapsulated in poly (ethylene glycol) diacrylate scaffold

Osteoarthritis (OA) is characterized by degenerative changes within joints that involved quantitative and/or qualitative alterations of cartilage and synovial fluid lubricin, a mucinous glycoprotein secreted by synovial fibroblasts and chondrocytes. Modern therapeutic methods, including tissue-engineering techniques, have been used to treat mechanical damage of the articular cartilage but to date there is no specific and effective treatment. This study aimed at investigating lubricin immunohistochemical expression in cartilage explant from normal and OA patients and in cartilage constructions formed by Poly (ethylene glycol) (PEG) based hydrogels (PEG-DA) encapsulated OA chondrocytes. The expression levels of lubricin were studied by immunohistochemistry: i) in tissue explanted from OA and normal human cartilage; ii) in chondrocytes encapsulated in hydrogel PEGDA from OA and normal human cartilage. Moreover, immunocytochemical and western blot analysis were performed in monolayer cells from OA and normal cartilage. The results showed an increased expression of lubricin in explanted tissue and in monolayer cells from normal cartilage, and a decreased expression of lubricin in OA cartilage. The chondrocytes from OA cartilage after 5 weeks of culture in hydrogels (PEGDA) showed an increased expression of lubricin compared with the control cartilage. The present study demonstrated that OA chondrocytes encapsulated in PEGDA, grown in the scaffold and were able to restore lubricin biosynthesis. Thus our results suggest the possibility of applying autologous cell transplantation in conjunction with scaffold materials for repairing cartilage lesions in patients with OA to reduce at least the progression of the disease.     

The in vitro effect of a lyophilized extract of wine obtained from Jacquez grapes on human chondrocytes

The present work was aimed at evaluating the in vitro effects of a lyophilized extract of wine (JW-E) obtained from Jacquez grapes (Vitis aestivalis-cinereaxVitis vinifera grapes) on the production of key molecules released in inflammatory disease utilising interleukin-1beta (IL-1beta) activated chondrocytes. The extract contains large amounts of phenolic components, in particular some flavonoids (flavan-3-ols, also known as catechins) and proanthocyanidins, as hydroxycinnamic acids and anthocyanins, that possess several biological features such as antiinflammatory and antioxidant effects and a "radical scavenger" activity too. In this study, we assayed the effect of JW-E on the production of key molecules released during chronic inflammatory events as nitric oxide (NO), prostaglandins E(2) (PGE(2)) and reactive oxygen species (ROS) in human chondrocytes culture, stimulated with proinflammatory cytokine interleukin-1beta. The JW-E proved to possess good ability against the harmfull effects of IL-1beta. Our data showed the protective effects of JW-E in cartilage alteration, that appears greater than that elicited by indomethacin, a not steroidal antiinflammatory drug (NSAID), commonly employed in joint diseases.     

Phosphodiesterase 8 (PDE8) regulates chemotaxis of activated lymphocytes

The immune system depends on chemokines to recruit lymphocytes to tissues in inflammatory diseases. This study identifies PDE8 as a new target for inhibition of chemotaxis of activated lymphocytes. Chemotactic responses of unstimulated and concanavalin A-stimulated mouse splenocytes and their modulation by agents that stimulate the cAMP signaling pathway were compared. Dibutyryl cAMP inhibited migration of both cell types. In contrast, forskolin and 3-isobutyl-1-methylxanthine each inhibited migration of unstimulated splenocytes, with little effect on migration of stimulated splenocytes. Only dipyridamole alone, a PDE inhibitor capable of inhibiting PDE8, strongly inhibited migration of stimulated and unstimulated splenocytes and this inhibition was enhanced by forskolin and reversed by a PKA antagonist. Following concanavalin A stimulation, mRNA for PDE8A1 was induced. These results suggest that in employing PDE inhibitor therapy for inflammatory illnesses, inhibition of PDE8 may be required to inhibit migration of activated lymphocytes to achieve a full therapeutic effect.     

Body shape variation and colour change during growth in a protogynous fish

Protogynous sequential hermaphroditism is very common in marine fish. Despite a large number of studies on various aspects of sequential hermaphroditism in fish, the relationship between body shape and colour during growth in dichromatic species has not been assessed. Using geometric morphometrics, the present study explores the relationship between growth, body shape and colouration in Coris julis (L. 1758), a small protogynous labrid species with distinct colour phases. Results show that body shape change during growth is independent of change in colour phase, a result which can be explained by the biology of the species and by the social control of sex change. Also, during growth the body grows deeper and the head has a steeper profile. It is hypothesized that a deeper body and a steeper profile might have a function in agonistic interactions between terminal phase males and that the marked chromatic difference between colour phases allows the lack of strict interdependence of body shape and colour during growth.     

Ethanol-induced oxidative stress in rat astrocytes: role of HSP70

Ethanol intake is associated with increase in lipid peroxidation and formation of reactive oxygen species in different cerebral areas, in neurons as well as in astrocytes. The latter's integrity is essential for the normal growth of neurons. In previous studies we observed, in different cerebral areas of both acutely and chronically ethanol-treated rats, correlation between ethanol-induced oxidative stress and the increased expression of HSP70 (70 kDa heat shock proteins), chaperonins having a protective and stabilizing effect on stress–induced cell injury. In this study we examined, in vitro, the role of HSP70 on chronically ethanol-treated rat astrocytes by transfection with an anti-HSP70 antisense oligonucleotide. The results show that treatment with ethanol, from 50 to 100 mmol/L, induces a dose-dependent increase in the production of reactive oxygen species and of HSP70 levels, together with an impairment of the respiratory chain activity and a decrease in cell viability. In addition, our data indicate a drastic reduction of cellular metabolism in HSP70-deprived astrocytes, particularly when these cells were also ethanol-treated. In fact, transfection with HSP70 antisense induced moderate oxidative damage in control astrocytes and, consequently, a drastic decrease in the viability of ethanol-treated cells, with the mitochondrial functionality being particularly affected. Our results confirm that heat shock proteins confer a survival advantage to the astrocytes, preventing oxidative damage and nuclear DNA damage as well, and suggest the development of new drugs exerting a cytoprotective role either in physiological, or pathological conditions. This revised version was published online in July 2006 with corrections to the Cover Date.     

Diapause affects cuticular hydrocarbon composition and mating behavior of both sexes in Drosophila montana

Envipnmental cues,mainly photoperiod and temperature,are known to control female adult reproductive diapause in several insect species.Diapause enhances female survival during adverse conditions and postpones progeny production to the favorable season.Male diapause(a reversible inability to inseminate receptive females)has been studied much less than female diapause.However,if the males maximized their chances to fertilize females while minimizing their energy expenditure,they would be expected to be in diapause at the same time as females.We investigated Drosophila montana male mating bchavior under short-day conditions that induce diapause in females and found the males to be reproductively inactive.We also found that males reared under long-day conditions(reproducing individuals)court reproducing postdiapause fermales,but not diapausing ones.The diapausing fies of both sexes had more long-chain and less short-chain hydrocarbons on their cuticle than the reproducing ones,which presumably increase their survival under stressful conditions,but at the same time decrease their attractiveness.Our study shows that the mating behavior of females and males is well coordinated during and afier overwintering and it also gives support to the dual role of insect cuticular hydrocarbons in adaptation and mate choice.     

Micropropagation of the endangered species Malus niedzwetzkyana for conservation biodiversity in Kazakhstan

In Vitro Cellular & Developmental Biology - Plant - Biodiversity conservation requires advanced and effective ex situ plant propagation techniques. The present study was conducted to optimize...